Head and body length of S. carolinensus is between 200-315
mm, tail length is 200-310 mm. Weights range from 200-1,000
grams. Upperparts are grey to greyish brown with paler, sometimes
whitish, underparts. There are two molts per year, but the tail
fur is only shed once each year.
S. carolinensus inhabits deciduous, coniferous and tropical
forests, both humid and arid. Most of their time is spent in
the treetops, but they do come down to forage for food and bury
nuts and acorns. Nests are constructed in hollow tree cavities
or in tree branches during the summer. While S. carolinensus
may have a particular den that is used for several years, others
are constructed as shelters used to escape from enemies. S.
carolinensus is primarily diurnal, but in the northern part
of its region, will forage midday during the winter months.
While Grey squirrels do not hibernate, they will remain in their
nests during very cold or stormy weather, unless it is necessary
for them to find food. S. carolinensus will migrate if
food stores become low. Mass migrations, which can involve thousands
of animals, occur when the food supplies are low and population
densities are high.

The diet of S. carolinensus consists of various nuts,
seeds, fruits, buds and young tree shoots. Acorns and hickory
nuts are favorites when available.

The gestation period for S. carolinensus is about 44
days, with an average litter size of 3, but as many as 9 young
have been recorded in a single litter. Weighing less than an
ounce, the babies are born naked and blind. Fur begins to grow
at about 14 days and the eyes open around 30-32 days. They remain
in the nest for approximately six weeks. Females generally breed
within their first year.

S. carolinensus is found in E Texas (USA) to Saskatchewan
(Canada) and east to the Atlantic coast. Introduced into Britain,
Scotland, Ireland, Italy, Australia, South Africa and various
localities in W North America.